I’m not sure how often big structures get blown up in this region, or if that’s the sort of thing you’ll go out of your way to watch.

But if explosive change strikes you as a marvel of ingenuity, than Ottawa’s Central Experimental Farm near Dow’s Lake is the place to be this Sunday – from a safe distance, of course. That’s where a large, brick structure is going down with a bang at 7 a.m. Indeed, this is said to be the biggest controlled demolition in the city’s history.

The Sir John Carling Building (described as an “obsolete federal building tower”) will hopefully tumble down without mishap into 40,000 imperial tonnes of rubble. (Here’s the official summary of the building and the future of that site.)

The project went to real pros: Idaho-based Advanced Explosives Demolition Inc. under the watchful eyes of Eric “master blaster” Kelly:

The surrounding area is open Experimental Farm property, except for one critical obstacle. Just metres away, on the northwest side, sits a small, one-storey former cafeteria building known as the “West Annex.” It’s a heritage site the government wants protected.

So Kelly has to get the tower to fall to the southeast, just enough to miss demolishing it.

“This is a tough one,” says master blaster.

Kelly estimates he has “shot” close to 1,000 structures in his 35-year career. He holds world records. In 1994, he lit the fuse on 5,400 kilograms of explosives and toppled a 251,000-square-metre Sears building in Philadelphia, the largest U.S. structure ever demolished with explosives.

Advanced Explosives Demolition was the company hired to take down the Lake Champlain Bridge back in December of 2009, as seen here in slow-motion.